000
AXNT20 KNHC 270526
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN SEP 27 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 24W/25W S OF 17N MOVING W NEAR 15 KT. 
WELL DEFINED INVERTED-V CURVATURE IS OBSERVED ALONG THE WAVE 
AXIS. WAVE COINCIDES WITH A MOISTURE MAXIMUM AS INDICATED IN THE 
TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...DUE TO THE SAHARAN 
DUST THAT COVERS THE N PORTION OF THE WAVE...SCATTERED MODERATE/ 
ISOLATED STRONG CONVECTION IS EMBEDDED WITHIN THE ITCZ FROM 
9N-12N BETWEEN 23W-27W. 

TROPICAL WAVE IS ALONG 70W/71W S OF 18N MOVING W NEAR 15 KT. 
WAVE REMAINS IN AN AREA OF RATHER DRY STABLE AIR...THUS 
SIGNATURE OBSERVED ON INFRARED SATELLITE IMAGERY AND NO 
ASSOCIATED SHOWERS OR CONVECTION.  

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 13N15W 8N33W 10N55W 10N62W. 
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE 
FROM 5N-10N BETWEEN 27W-38W. 

...DISCUSSION...

GULF OF MEXICO...
THE STATIONARY FRONT THAT HAS REMAINED OVER THE W GULF FOR THE 
PAST FEW DAYS IS FINALLY DISSIPATING ENTERING FROM LOUISIANA 
OVER VERMILION BAY CONTINUING ALONG 28N94W TO 26N96W. A SURFACE 
TROUGH IS OFF THE E COAST OF MEXICO FROM 25N97W INTO THE BAY OF 
CAMPECHE TO NEAR 19N96W. SCATTERED SHOWERS/THUNDERSTORMS ARE IN 
THE E BAY OF CAMPECHE S OF 21N E OF 95W WITH SCATTERED SHOWERS/ 
ISOLATED THUNDERSTORMS WITHIN 90 NM ALONG THE E COAST OF MEXICO 
FROM 19N-26N. A SURFACE TROUGH IS TO THE E OF THE DISSIPATING 
FRONTAL BOUNDARY EXTENDING THROUGH PENSACOLA FLORIDA TO 29N88W 
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 28N TO 
INLAND OVER FLORIDA BETWEEN 84W AND THE SURFACE TROUGH. BROAD 
UPPER RIDGE REMAINS ANCHORED OVER THE CENTRAL GULF NEAR 26N87W 
EXTENDING AN AXIS NE ACROSS THE CENTRAL FLORIDA PENINSULA AND SW 
TO NEAR TAMPICO MEXICO FORCING SHOWERS/THUNDERSTORMS THAT HAVE 
DEVELOPED INLAND OVER THE FLORIDA PENINSULA E TOWARD THE W ATLC 
WITH ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS IN THE SE GULF 
FROM THE FLORIDA KEYS TO FORT MYERS E OF 83W.  

CARIBBEAN SEA...
A SHARP UPPER TROUGH EXTENDS FROM THE CENTRAL ATLC OVER THE 
DOMINICAN REPUBLIC THROUGH THE GULF OF HONDURAS TO OVER THE 
YUCATAN PENINSULA NEAR S BELIZE SPLITTING THE CARIBBEAN WITH THE 
NW CARIBBEAN HAVING ELY UPPER FLOW AND S AND E CARIBBEAN HAVING 
W UPPER FLOW. THE S CARIBBEAN HAS AN ABUNDANCE OF TROPICAL 
MOISTURE PRODUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER 
THE E CARIBBEAN FROM 14N-18N E OF 69W ACROSS THE LESSER ANTILLES 
AND SCATTERED SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS S OF 
14N W OF 76W. FRESH TO STRONG EASTERLY TRADE WINDS CONTINUE 
ACROSS MUCH OF THE AREA WITH THE REMAINDER OF THE CARIBBEAN 
REMAINING CLEAR AGAIN TONIGHT. 

ATLANTIC OCEAN...
BROAD UPPER RIDGE ANCHORED IN THE GULF OF MEXICO COVERS THE W 
ATLC AND COMBINED WITH A SHARP UPPER TROUGH IN THE CENTRAL ATLC 
THAT EXTENDS ALONG 32N57W THROUGH AN UPPER LOW NEAR 26N60W ALONG 
23N63W OVER THE DOMINICAN REPUBLIC INTO THE CARIBBEAN ARE 
PRODUCING STRONG NLY UPPER WINDS OVER THE W ATLC W OF THE UPPER 
TROUGH TO NEAR 75W. THE UPPER TROUGH IS SUPPORTING A COLD FRONT 
THAT ENTERS THE REGION NEAR 32N51W TO 29N64W AND A WEAKENING 
SURFACE TROUGH THAT EXTENDS FROM 28N64W TO 23N68W. THIS IS ALL 
PRODUCING A LARGE AREA OF SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS WITHIN 150 NM OF LINE FROM 28N64W 29N52W TO BEYOND 
32N48W AND FROM 22N-26N BETWEEN 56W-59W. A 1008 MB LOW... 
REMNANTS OF TROPICAL DEPRESSION EIGHT...IS IN THE E ATLC NEAR 
19N36W WITH A SURFACE TROUGH EXTENDING FROM 24N35W THROUGH THE 
LOW TO 16N36W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS 
TO THE E OF THE LOW FROM 17N-22N BETWEEN 32W-36W. OTHERWISE THE 
REMAINDER OF THE E ATLC IS DOMINATED BY A SURFACE RIDGE N OF 23N 
E OF 45W. THE LAST VISIBLE SATELLITE IMAGES SHOW THE SURGE OF 
SAHARAN DUST COVERING THE FAR E TROPICAL ATLC FROM 14N-25N 
ACROSS THE CAPE VERDE ISLANDS TO 30W.

$$
WALLACE